a couple courses around me have natural pads...the best ones are usually the simplest ones - large worn in, packed down patches of dirt. (they cannot be in a place where rain runoff will get to them, so keep them in relatively high-ground areas). The worst ones are when they start putting logs and crap framing the outside of the tee. That kind of stuff is just going to make more work for you in the long run, even if it looks nice. just my 2cents, take it as a grain of salt

Unfortunately, I don't have the technical expertise needed to answer your questions.

I've seen a fair array of natural pads ranging from simple grass to rutted dirt replete with roots sticking out.

It's hard to say what would be best for your case without knowing more about the course the tees would go on. How many holes? Average hole length? What terrain types exist on the course? How heavy do you expect the traffic to be?

The best ones I've seen have a small diameter screened gravel overlay without log framing. They are periodically maintained, re-filled and tamped.
Great example= Black Falls or Cherry Hill in Montgomery,VT. These are just as good as concrete imo.

whatever u do....go out to the course in the middle of a rain deluge..this is the only way to truly understand where the driest parts of the land are....I was shocked when I did this, things were wettest where I thought it'd be dry and vice versa, and it allowed me to find the driest areas for tees and baskets

I think natural tees work best if you are able to simply put some pavers down sunk in the ground and flat...this will allow you to move them if they wear out.....also try to place them in inconspicuous areas..along woodlines or under trees where it wont look like an ugly brown mark in an otherwise pretty grass field